The invention relates to an elastic vehicle tire having a tire cavity which is enclosed by a running strip supporting the tread surface and a side wall formed on each side of the running strip and having at least one noise dampening insert arranged in the tire cavity or one noise dampening insert arrangement arranged in the tire cavity.
Such vehicle tires are used in motor vehicles, trailers and semitrailers, and they are also referred to as vehicle pneumatic tires. These tires are cushion tires whose stability is achieved primarily by air pressure introduced into the cavity. The cavity of such a vehicle tire is formed by a running strip supporting the tread surface. The side walls abut against said running strip on both sides. The side walls each support, at their free end a bead for mounting the tire on a wheel rim which rests against the rim well as well as the rim edge. In the case of tubeless tires, the bead rests sealingly against the rim edge or the rim well, so that the cavity formed by the vehicle tire is closed off by the rim.
Rolling noises are generated by the tire tread pattern on the tread surface when the tread surface is rolled on a paved road surface. The resonance oscillations that are responsible for the rolling noises are conveyed as air-borne sound to the environment and as solid-borne sound through the wheel, the vehicle wheel suspension and the car body to the interior of the vehicle. In order to reduce the rolling noise, and particularly the resonance oscillations, vehicle tires have been developed which have an insert or a corresponding insert arrangement for noise dampening. These noise dampening inserts are typically arranged on the inner side of the running strip. Additionally, the inserts can also extend at least partially along the side walls. Foam inserts are often introduced into the tire cavity as noise dampening inserts. As described in DE 30 42 350 A1, they are connected to the inner side of the tire either by gluing, or by vulcanization. DE 20 2008 009 008 U1 discloses a vehicle tire with a viscoelastic foam insert as noise dampening insert.
Although noise damped vehicle tires are desirable, particularly for reasons pertaining to environmental compatibility, these tires have not yet experienced a widespread introduction on the market. One of the reasons is that the tires heat up during rolling, particularly when taking curves. Even though a certain amount of heating of the running strip with its tread surface is advantageous in order to increase the adhesion to a paved road surface, its wear increases with increased heating of the tire. However, in the case of noise damped tires, heating of the running strip is often above an acceptable level. Consequently, the wear of such a tire is increased in comparison to a tire without noise dampening. It is assumed that the reason for stronger heating in noise damped tires is that the noise dampening foam insert on the inner side of the running strip acts as a thermal insulator, preventing or eliminating the radiation of heat into the internal space of the tire. In order to counter this disadvantage of noise damped vehicle tires, it has been proposed to incorporate heat conducting particles in the foam insert to create a heat conducting path from the inner wall of the tire through the noise dampening insert to the tire cavity, as described in JP 2005-104314 A and JP 2007-230544 A. In contrast, DE 20 2008 009 008 U1, proposes to incorporate microencapsulated phase transition material as latent heat storage material in the foam insert, in order to postpone the time when the tire reaches its still admissible peak temperature. In this conception, heat is consumed by the phase transition of this material. In this manner, temperature peaks during driving operation can be buffered with regard to tire heating.
These solutions for removing heat from the inner side of the running strip of the tire have the disadvantage that additional material has to be incorporated in the foam, adding to the weight of the noise dampening foam insert. Moreover, during the manufacture of the foam insert, one must ensure that the incorporated particles are arranged such that the desired heat removal from the inner side of the running strip occurs as intended. Consequently, the particles used to form the desired heat removal paths have to abut against each other throughout the noise dampening layer. It has been found that the manufacture of foams with such incorporated particles is often problematic.
The foregoing example of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.